Making a USB DAC and Headphone Amp

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Making Myself a USB DAC + Headphone Amp

I need a DAC for my AKG K702. However, the more I looked at commercially available a.k.a. “audiophile” products, the more snake oil I smell. So even before I ordered my CEntrance DACPort Slim, I was already looking into how I can reinventing the wheel

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I use OSHPark for prototyping PCBs. I decided to use their 4-layer FR-408 stackup simply for an un-broken ground layer. Turns out that the analog signals can easily fit on the top layer, so I allocated the power layer to the negative rail, and the bottom layer to positive rails.

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The DAC + Filter module works! It produces reasonably clean line-level audio signal as expected.

 

Making a USB DAC and Headphone Amp

Trailer Brake Light Controller

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Kevin H. Patterson designed this solution for trailer light wiring after installing a towing hitch on his vehicle:

Custom Brake Light Controller Expands your Trailer’s Capabilities

This is a power module designed to control trailer lights based on signals from your vehicle’s lighting circuits. Most vehicles have at least 4 separate circuits: Running (Tail) Lights, Brake, Left Turn, and Right Turn. Most basic trailers have a 4-wire connector with only 3 signals: Running (Tail) Lights, Left Turn, and Right Turn. The trailer does not have a separate circuit for Brake lights; applying the Brake is supposed to light up both the Left and Right Turn signals together.

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The board can be purchased on Tindie:

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Creltek 3-Line Trailer Light Converter

4-Line to 3-Line Combining Tail Light Power Module for 12V Systems

 
Trailer Brake Light Controller

Normal schedule during Lunar New Year 2017

Happy Lunar New Year!

We would like to let our customers know that all of our boards are manufactured in the United States, and OSH Park will be operating on a normal schedule through Lunar New Year:

Shipping Information and Turnaround Times

There are two periods of time to think about when making your order:

  • Fabrication time between when you place your order and when we receive boards from the fab.
  • Shipping time between when we ship and when the post office delivers your order to you.

All PCBs ship from Lake Oswego, Oregon, and are fully manufactured in the United States.

Normal schedule during Lunar New Year 2017

thingSoC Grovey on Crowd Supply

thingsoc_modelthingSoC is an Open Source socket system for IoT development and has just launched a new Crowdy Supply campaign:

thingSoC “Grovey”

Build any IoT or Networked device you can imagine!

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The thingSoC Grovey! platform gives you the freedom to choose from hundreds of existing sensors, actuators, and radios to quickly create new electronic systems, in plug together configurations that were not possible before. Easily mix together different CPUs, Radios, and Peripherals, like Servos, Motors, Relays, Sound and Lights, and then program them in your choice of Integrated Development Environments (IDE).

The thingSoC Grovey! series combines access to the Seeedstudio Grove system, and the Mikrobus “Click” system, to give you the widest selection of radios, sensors, and actuators available today.

The thingSoC Grovey Series files are available on GitHub:

thingSoC Grovey on Crowd Supply

DIY Vacuum Pickup Tool

We are always surprised how much useful hacking gear is in the typical craft store. You just have to think outside the box. Need a hot air gun? Think embossing tool. A soldering iron? Check the stained glass section. Magnification gear? Sewing department. We’ve figured out that people who deal with beads use lots of fine…

via [Dave’s] Not Just a Member of the Air Club for Tweezers — Hackaday

DIY Vacuum Pickup Tool

iceRadio SDR

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From the Hackaday blog:

Ice, Ice, Radio Uses FPGA

Building a software defined radio (SDR) involves many trades offs. But one of the most fundamental is should you use an FPGA or a CPU to do the processing. Of course, if you are piping data to a PC, the answer is probably a CPU. But if you are doing the whole system, it is a vexing choice.

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The FPGA can handle lots of data all at one time but is somewhat more difficult to develop and modify. CPUs using software are flexible–especially for coding user interfaces, networking connections, and the like) but don’t always have enough horsepower to cope with signal processing tasks (and, yes, it depends on the CPU).

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[Eric Brombaugh] sidestepped that trade off. He used a board with both an ARM processor and an ICE FPGA at the heart of his SDR design. He uses three custom boards: one is the CPU/FPGA board, another is a 10-bit converter that can sample at 40 MSPS (sufficient to decode to 20 MHz), and an I2S DAC to produce audio. Each board has its own page linked from the main project.Z

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The iceRadio project page has additional details:

Design files and source code are available on GitHub:

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iceRadio SDR

SKiDL: Script Your Circuits in Python

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SKiDL: Script Your Circuits in Python

SKiDL is very, very cool. It’s a bit of Python code that outputs a circuit netlist for KiCAD. Why is this cool? If you design a PCB in KiCAD, you go through three steps: draw the schematic, assign footprints to the symbolic parts, and then place them. The netlist ties all of these phases together […]

The source code is available on GitHub:

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SKiDL: Script Your Circuits in Python

Surface-Mount Edge Connectors

FacelessTech designed this small board to act as a surface-mount edge connector:

SMD edge connectors

So you want to joint two boards together, You decide to use through hole female and male 2.54 pitch headers. Normally you would use through hole than ether have a 90 degree headers or just bend them over. For years this is how I did it, I would have to make sure I made sure the holes were just the right distance from the edge of the board.

The KiCad design files are available on GitHub:

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Surface-Mount Edge Connectors